10 Question-Answer on kinetic theory of gases
1. For a gas, the r.m.s. speed at 800 K
(a) Four times the value at 200K
(b) Half the value at 200 K
(c) Twice the value at 200 K
(d) Same as at 200 K
Ans: ( c)
2. For a gram-molecule of a gas, the value of the constant R in the equation PV =RT is nearly
(a) 2 cal/K
(b) 10 cal/K
(c) 0.2 cal/K
(d) 200 cal/K
Ans: (a)
3. The mean translation kinetic energy of gas molecule at temperature T is (k-Boltzmann constant).
(a) KT/2
(b) kT
(c) 3kT/2
(d) 2kT
Ans: (c)
4. A litre of an ideal gas at 27˚C is heated at a constant pressure to 297 ˚C. Then the final volume is approximately
(a) 1.2 litres
(b) 1.9 litres
(c) 19 litres
(d) 2.4 litres
Ans: ( b)
5. The internal energy of a gram-molecule of an ideal gas depends on
(a) Pressure alone
(b) Volume alone
(c) Temperature alone
(d) Both on pressure as well as temperature
Ans: (c)
6. The relation PV = RT can describe the behavior of a real gas at
(a) High temperature and high density
(b) High temperature and low density
(c) Low temperature and low density
(d) Low temperature and high density
Ans: (b)
7. If the pressure in a closed vessel is reduced by drawing out some gas, the mean-free path of the molecules:
(a) Is decreased
(b) Is increased
(c) Remains unchanged
(d) Increases or decreases according to the nature of the gas.
Ans: (b)
8. The temperature of a gas is measure of
(a) The average kinetic energy of the gaseous molecules
(b) The average potential energy of the gaseous molecules
(c) The average distance between the molecules of the gas
(d) The size of the molecules of the gas.
Ans: (a)
9. The pressure exerted on the walls of container by a gas due to the fact that gas molecules are :
(a) Losing their kinetic energy
(b) Sticking to the walls
(c) Changing their momenta due to collision with walls
(d) Getting accelerated towards the wall
Ans: ( c)
10. If the volume of a gas is doubled at constant pressure, the average translational kinetic energy of its molecules will:
(a) Be doubled
(b) Remain same
(c) Increase by a factor √2
(d) Become four times.
Ans: (a)